Amazon's cloud is big enough to be the fifth-largest business software company in the world

AWS could surpass SAP to become the fourth-biggest business software company before 2020.

Amazon Web Services CEO Andy Jassy.

CNBC

Amazon's cloud business has grown so quickly in the past decade that it's now the fifth-largest business software provider in the world.

Revenue at Amazon Web Services jumped 43 percent in 2017 to $17.5 billion, representing about one-tenth of Amazon's total revenue, the company said this week. The only publicly-traded business software companies ahead of AWS are Microsoft, IBM, Oracle and SAP, according to data from FactSet.

AWS is far and away the leading provider of cloud infrastructure technology, and it has proven that Amazon can diversify beyond e-commerce. Microsoft, Google, IBM and others are all chasing AWS in the cloud.

Assuming AWS continues to grow as much as it did last year, it could pass SAP in size before the end of 2019. SAP's 2017 revenue of $26.5 billion was up 6 percent, and the company expects the same growth rate in 2018. Analysts are currently projecting 38 percent growth at AWS this year, according to FactSet.

With its lineup of cloud-based databases, data analytics tools, productivity apps and raw computing capacity, AWS is almost twice as big as Salesforce, which generated sales of $9.9 billion over the past four quarters, growing 25 percent.